I’m getting a lightweight wheelset for my hardtail (on-456 carbon). I’m currently using it with rigid exotic-carbon forks and singlespeed, and am planning on using it with skinny cx tyres for general xc and hopefully some cyclocross racing.

I just went to click “buy”, but saw they have a 26″ or 27.5″ option…
I’m not sure what to get now!

From a quick google, it doesn’t look like there are many (any?) 27.5″ cx tyres around (found some 26″ ones)which might be a problem.

Which should I go for? I’m pretty sure a 27.5 will fit in the frame no problem, and definitely will in the fork. But does that extra little bit really make any difference??
Or will it just be a pain in the a$$ as I wont be able to switch tyres with my other 26″ wheels if I need to?

Depends. Do you want the cyclocross course to come alive under your wheels?

It’ll make bugger all difference unless you can squeeze some 29er wheels in there.

You can actually squeeze 29 in wheels in a C456. A mate has done it and said it was fine. He posted the evidence on here a while back. Another mate has 650bs on his C456 and loves it. Personally, I’d stick with 26 – it’s what the frame is designed for, you know you can get the tyres you want and you won’t be aware that the trail is failing to come alive under you (unless you’re in marketing?).

650b wheels on a bike not designed for it is a massive PITA waiting to happen. Firstly, tyre availability in 650b is poor still. Secondly, you’d need to be running quite narrow tyres, probably 1.75″ or narrower, to not cause any issues with frame and fork clearance and I don’t know of any good narrow 650b tyres (if you want 2.2″ or above there seems to be lots, but none narrower I know of). Thirdly, it has the potential to raise the BB height slightly, which may affect the handling. Lastly, what would you actually benefit from by doing it?

If you stick with the wheel size that your frame was designed around, you won’t come into any problems, and you can chop and change between skinny CX tyres and big freeride tyres as you see fit!

tosh… ignore all the advice above. lobby your local mp for a new 26.75″ wheel size… it really will make the trail come right alive..

As mboy says, the bb and tyre clearance will be a pita. You’ll end up running lower volume tyres than if you had a 26er wheel set, which means you’ll have exactly the same outer tyre diameter, but it’ll rattle the sh1t out of you.

Joe, you can borrow my wheels with 2.25 Rons on for a while and see what you think?

Also, thinnest tyres currently available are Maxxis Beaver in a 2.0, which should be alright for cross.

You might be making any warranty void, bb too high, mm makes a difference. Swapping wheel sets can be a bit troublesome too with chain wear, rear cassette wear, swapping chains might be an idea too. I went through this, and decided not too with my 26 ht.

Mboy I think you got right at what I was really thinking… “what would I actually benefit from getting them”. Think I’ll stick with the 26 and be able to use whatever tyres I want, no more new standards! I appreciate the opinions.

And cheers Mike, I was actually going to ask you when I get back tomorrow haha. Are you working this week? I need to ride lots!